|  | 5.4 | IGRP Operations
| 5.4.6 | The maximum hop count of IGRP
IGRP has a maximum hop count of 255, which is normally set lower than the default 100. Because IGRP uses triggered (flash) updates, counting to 100 may not take too long. However, you should set the maximum hop count to something smaller, unless you have an enormous network. It should be a number at least as large as the maximum number of routers a route might ever have to go through in the network. If you exchange IGRP routing with an external network, the hop count must include your network plus that external network. When you compute hop count, take into account what the configuration would look like if a few lines went down. Here's a sample router statement that uses all the features explained in this section; you should use your own network number in place of 128.6.0.0: Router(config)# router igrp 46 timers basic 15 45 0 60 network 128.6.0.0 no metric holddown metric maximum-hop 50 With this statement, routing generally adapts to change within 45 seconds, assuming that the keepalive interval, which is the period of time between messages sent by a network device, has been set to 4.
| Lab Activity
| In this lab you will work with Cisco's Interior Gateway Routing Protocol (IGRP). Routing protocols are used by routers to communicate between themselves in order to exchange information about the networks they can reach and the desirability of the routes available.
| Lab Activity
| In a previous lab, you saw how to set up the RIP routing protocol on Cisco routers. In this lab you will configure the routers to use IGRP and see how IGRP uses metrics to select the best path.

| Lab Activity
| In this lab you will use the shareware utility NeoTrace to determine the path that data travels through an Internetwork.